If you’re trying to conceive, you’ve probably heard about the importance of factors such as age, nutrition, lifestyle, hormone balance, and overall health. But did you know that your genes may also influence your fertility journey?
Your DNA can provide valuable insights into how your body regulates hormones, processes nutrients, manages inflammation and oxidative stress, and clears environmental toxins. All of this can affect reproductive health and may influence factors such as egg quality, ovulation, ovarian reserve, and the ability to support a healthy pregnancy.
While genetic testing cannot tell you whether you will or won’t become pregnant, it can help uncover inherited tendencies that may be affecting key fertility pathways.
Your genes are not your destiny
One of the most important things to understand about fertility genetics is that genes do not determine your future.
Your genes provide the blueprint for how your body functions, but they are only one part of the picture. Small variations (called SNPs – Single Nucleotide Polymorphisms) within genes can influence how efficiently your body regulates hormones, supports ovulation, metabolises nutrients, and maintains reproductive health. These variations can help explain why some people need higher levels of certain nutrients or are more vulnerable to environmental factors that can impact fertility.
What matters most is how these biological systems are functioning right now.
Healthy ovulation, balanced hormones, good nutrition, quality sleep, stress management, and overall wellbeing remain the foundations of fertility. Genetic testing simply helps identify areas where your body may benefit from additional support, allowing for a more personalised approach to optimising reproductive health.
Why fertility genetics matters
Conception and a healthy pregnancy depend on a number of biological processes working in sync. Methylation supports DNA repair and cell division, both essential for egg quality and early embryo development. Hormone metabolism affects how efficiently your body produces and clears oestrogen, which influences ovulation and implantation. Detoxification pathways determine how well your body clears environmental toxins and excess hormones, protecting eggs from damage. Oxidative stress, when unmanaged, can affect mitochondrial function within egg cells, which are particularly sensitive given how energy-intensive conception is.
The genes that influence female fertility
From a functional medicine perspective, a specific group of genes has the most clinical relevance for women trying to conceive. Together, these genes affect methylation, hormone metabolism, detoxification, oxidative stress, nutrient status and ovulatory function.
Methylation and DNA repair
MTHFR (C677T and A1298C), MTR and MTRR, and PEMT are all involved in methylation, the process your body uses for DNA repair, cell division and homocysteine metabolism. MTHFR is the most well-known of these, affecting how efficiently folate is converted into its active form, with some genetic SNPs resulting in less than a third of the methylation efficiency of others. This is worth knowing about yourself anyway, but doubly so when you are trying to grow a new human, as that methylation process is involved in just about everything, including egg quality, implantation and neural tube development.
Detoxification and toxin clearance
Genes such as GSTM1, GSTP1 and GPX1 help regulate some of the body’s most important detoxification and antioxidant pathways. These genes are involved in the production and recycling of glutathione, referred to as the body’s “master antioxidant” because it neutralises free radicals, protecting cells from oxidative damage and supporting the safe removal of environmental toxins.
In a similar way to MTHFR, various combinations of glutathione-affecting SNPs can make a significant impact on glutathione function. Equally, a few tweaks (E.g. NAC, selenium), depending on your genetics, can make an enormous difference to real-world outcomes.
When it comes to fertility, understanding your variations in these genes can provide valuable information into how you can efficiently detoxify the chemical exposures of modern life, such as air pollution, pesticides, plastics, and other environmental toxins. If your genetic test identifies slow tendencies in these genes, it doesn’t mean infertility. Instead, it highlights an opportunity to be proactive in managing those gene pathways with targeted nutrition, antioxidant support, and lifestyle modifications to reduce toxic exposure and to focus on strengthening your detoxification capacity. By supporting glutathione production, you may help protect egg quality, support healthy implantation and create an optimal environment for pregnancy.
Oxidative stress and egg quality
Mitochondria are often referred to as the “powerhouses” of our cells because they generate cellular energy and, in particular, the energy needed for reproduction – from egg maturation and ovulation through to fertilisation and early embryo development. In fact, egg cells contain some of the highest concentrations of mitochondria in the entire body, making them particularly sensitive to free radical damage and oxidative stress. The SOD2 gene acts as part of the body’s natural antioxidant defence system, helping to protect mitochondria from this damage. However, some SOD2 SNP variations can impact the body’s ability to neutralise oxidative stress, which can compromise mitochondrial efficiency and affect egg quality and embryo development.
Knowing your genetic SOD2 variation allows you to take proactive steps to support mitochondrial energy through personalised nutrition, antioxidant-rich foods, and lifestyle strategies to optimise cellular energy production and mitochondrial protection.
Nutrient metabolism
FADS1 and FADS2 affect how well your body converts plant-based omega-3s into DHA, which is important for egg quality and hormone production. These genes are an excellent example of how genetics can influence fertility and pregnancy outcomes. Variants within the FADS1 and FADS2 genes can affect how efficiently the body converts plant-based omega-3 fats (ALA), found in foods such as flaxseeds, chia seeds and walnuts, into the biologically active forms EPA and DHA. For individuals carrying these variants, relying solely on plant sources of omega-3s may not provide adequate amounts of the long-chain omega-3 fats needed for optimal reproductive health.
DHA is particularly important during the preconception period and throughout pregnancy. It plays a critical role in egg quality, embryo development, placental function and healthy pregnancy outcomes. As pregnancy progresses, especially during the third trimester, a baby’s demand for DHA increases dramatically as the brain, nervous system and eyes undergo rapid development. The developing baby will prioritise its own DHA needs, drawing on maternal stores to support this critical growth phase.
If a mother’s omega-3 stores are already low, this increased demand can further deplete her reserves, potentially contributing to symptoms such as fatigue, low mood, poor concentration and the memory lapses often referred to as “baby brain.” While many factors contribute to these symptoms, inadequate DHA status may play a role in some women.
For women with FADS1 or FADS2 variants, maintaining adequate omega-3 levels becomes even more important. Reduced conversion efficiency means they may be more reliant on preformed DHA and EPA from oily fish, seafood or high-quality omega-3 supplements to achieve optimal levels. When combined with nutritional testing to directly measure omega-3 levels and dietary assessment, genetic testing can help identify women who may have a higher requirement for these essential fats before and during pregnancy.
This highlights an important principle of fertility genetics: genes do not determine outcomes, but they can influence nutritional requirements. Understanding these genetic differences allows for more personalised nutrition and lifestyle strategies that support fertility, a healthy pregnancy and optimal brain development for the next generation.
Does MTHFR affect fertility?
MTHFR is one of the most commonly searched genes in fertility planning. This gene affects how efficiently your body converts folate into its active form, which is essential for methylation, DNA repair and homocysteine metabolism.
A less efficient MTHFR variant does not mean you cannot conceive. It simply means your body may need more support in converting and using folate, particularly given its importance for egg quality, implantation and neural tube development. For many women, this information can inform decisions around supplementation and nutrient support ahead of and during pregnancy. If you’re going to take a pregnancy multivitamin, knowing whether the form of folate in it is right for your body is important.
Why interpretation matters
Let’s look at a real-world example using the widely discussed MTHFR gene SNP.
Imagine two women who both carry the same MTHFR gene SNP. On paper, their genetic results appear identical, yet their fertility journeys look completely different.
The first woman follows a nutrient-dense diet rich in leafy greens, colourful vegetables, quality protein and healthy fats. She has good folate, vitamin B12 and vitamin B6 status, healthy blood sugar regulation, low levels of inflammation, well-managed stress and a balanced lifestyle. Her body is able to effectively support methylation pathways, hormone metabolism and healthy egg development, and she conceives without difficulty.
The second woman carries the very same MTHFR variant, but her overall health picture is different. She has suboptimal folate and B12 levels, elevated homocysteine, insulin resistance, chronic stress, poor sleep and a diet low in key nutrients needed to support methylation. These factors can influence hormone balance, egg quality, inflammation and reproductive function, creating additional challenges when trying to conceive.
The difference in their reproductive health is not simply the presence of the MTHFR gene SNP but how that genetic predisposition interacts with their nutrition, lifestyle, metabolic health and environment.
“Two people can carry the exact same gene variant and have completely different fertility outcomes because what matters most is how that variant interacts with your nutrition, your lifestyle, and your overall health. That’s where the real opportunity lies for making a difference.”
– Nina Crawford
This concept is known as gene expression. While we cannot change the genes we inherit, we can influence how they function or are expressed through targeted nutrition, supplementation, and lifestyle strategies. This is why two people with the same gene SNP can experience very different health and fertility outcomes.
When interpreted alongside your broader health picture, genetic testing can provide valuable insights into areas where additional support may be beneficial. Rather than focusing on a single gene, the goal is to understand how your unique genetic blueprint interacts with your medical history, symptoms, pathology results, lifestyle and diet to create a more complete picture of your fertility and identify opportunities to optimise your health before conception.
Want to know what your genes mean for you? A qualified practitioner like Nina can guide you through the available testing options and help translate your results into meaningful, personalised recommendations. Book to get started.
